Pneumatic tire.



F. REDDAWAY. PNEUMATIC TIRE. APPLICATION FILED in. 1a. 1908.

922,63 1 Patented May 25, 1909.

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FRANK REDDAWAY, PENDLETON, MANCHESTER, ENGLAND.

PNEUMATIC TIRE.

Specification of Letters Patent.

Patented May 25, 1909.

Application filed February 18, 1908. Serial No. 416,599.

To all whom it may concern:

Be it known that I, FRANK REDDAWAY, a subject of Great Britain, residingat Cheltenham street, Pendleton, Manchester, in the county of Lancaster,England, manufacturer, have invented new and useful Improvements inPneumatic Tires, of which the following is a specification. I

My invention relates to the covers of pneumatic tires, particularlyapplicable for motor-cars and similar heavy road vehicles, which tirecover embodies means for preventing skidding of such vehicles onslippery roads or when turning abrupt corners, and also for preventingdamage to the tires when they are under excessive compression.

In the accompanying drawing, Figure 1 indicates a section of a tirecover made in accordance with my invention. Fig. 2 is a portion of asection of tire cover showing a modification. Figs. 3 and 4 show detailparts of the invention.

The tire cover is used in conjunction with an air tube in the usual wayand it may be made in any convenient manner for securing to any one ofthe various kinds of rim,

as the method of attaching the cover to the rim forms no part of myinvention.

\Vhen making a tire cover in accordance with my invention instead ofmolding the rubber tread with a complete arch or convexity as is theusual practice, I form the tread with a double convexity a a obtained byproviding a central circumferential 'cav- The double arch or convexity aa is thus disposed at each side of the tire cover as is apparent fromthe drawings. The tire has two points of contact with the groundprovided by the two separate or twin side treads a a. These two separatetreads constitute very eflicient means for the prevention of sideslip orskidding. An'important means for preventing such skidding or side slipis obtained by the aid of a rope c of fiber or fibrous material disposedwithin and practically filling up the central cavity of the tire cover.This rope 0 provides an additional contact surface or tread and toprevent the rope from stretching it is provided with a core of metal. Asshown in Fig. 2 this metallic core 0 may take the form of an endlessring of solid wire of suitable gage, although, as indicated in Fig. 1,the metallic core 0 preferably consists of several strands of wire,which would provide a more flexible core than the solid wire and wouldnot be so liable to snap under sudden stress. Instead of wire I may usea flexible metallic chain c, as shown in Fig. 4. In any case the core 0is first made in the form of an endless ring of the required diameterand around such endless ring, a suitable fiber is wrapped, plaited orotherwise served to obtain an endless rope of the requisite diameter andstrength which is sprung into position in the cavity 6. To preventchafing of the rubber bed of the rope c owing to possible creeping ofthe rope, the cavity 1) is provided with a facing of canvas (5 or otherwear resisting material. The separate treads a, may be either rounded,as in Fig. 1, or flattened as in Fig. 2, and in the latter case, or inboth instances if desired, circumferential grooves a may be formed inthe tread.

The tire cover is molded and made up from rubber, strengthened in theusual manner by insertions of bias canvas 6, and in such a manner as toproduce the two con vexities with an intermediate concavity. Qwing tothe internal pressure exerted by theair-tube on the inner crown of thetire cover when the air tube is fully inflated, it is essential that Ishould provide some means for resisting such pressure in addition to theendless rope 0 otherwise there would be a tendency to force the coveroutward at the crown marked f thus destroying the value of the inventionby failing to preserve the central cavity 6. To prevent this, inaddition to the usual insertions of bias canvas 6 introduced as the tireis built-up, I provide the inner crown of the tire cover at the partmarked f with one or more circumfer Fig. 3, such a class of canvasserving to produce a most effective zone which insures the cavity 6being preserved under all circumstances. The pressure resisting bands 9forming the practically non-expansible intermediate zone may be appliedin separate lengths of gradually increasing width as shown in Fig. 1; ora length of the canvas or material may be wound circumferentially for asufficient number of convolutions. Such bands, although they maypossibly yield slightly to the internal pressure exerted on them, areunyielding enough to preserve the cavity 1) and so maintain the doubleconvexity or twin side treads a a. The non-expansible intermediate zoneproduced by the inserted canvas layers 9 serves,,when a slight orsuflicient separation has taken place, to anchor the convexities or twintire peripheries a, a, and to resist further spreading or separation andthus side-slip is prevented or more. quickly checked.

The rope 0 with metallic core, and the pressure resistingcircumferential bands 9 may be used together in the tire'cover orseparately as desired, in conjunction with the'tire cover.

I declare that what I claim is.

. In combination in a tire cover, the twin side treads forming thecentral circumferential cavity, an endless rope of fibrous material,located in said cavity, a metallic core in said ropeyand internalpressure resisting bands inserted in the material forming the coverbelow said cavity.

In testimony whereof I have signed my name to this specification in thepresence of two subscribingwitnesses.

FRANK REDDAWAY.

Witnesses:

JOSHUA EN'rwIsLE, ALFRED YATES.

